UX: newtab buttons in tab list and content menu should have the same behavior
UX: newtab buttons in tab list and content menu should have the same behavior

The standard action is adding one new tab when taping newtab button
whether there are newtabs in the list.

reviewed by James


Former-commit-id: 54a1c250645f3ed98b5576f4b5040d3f0c14e768
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser